8 votes

BM - Sulphite Covered Bridge



Covered Deck truss prior to burning

Photo belongs to national registry

View this photo at image1.nps.gov


The existing structure replaced a framed trestle bridge erected here in 1891 or 1892 by the Franklin and Tilton Railroad. This unusual bridge, built by the Bridge and Building Department of the Boston and Maine Railroad in 1896, appears to be the only deck-covered railroad bridge left in the United States. It was named Sulphite because of the large amounts of sulfur transported over the rail lines for use by the giant pulp and paper mills not far from the bridge. It is also known as the Upside Down Covered Bridge because the railroad track crosses over the top of the structure rather than running through its center. Service over the line was suspended in 1973. The bridge sides are boarded over with 7/8" siding and the ends are closed. There was a fire inside the bridge on October 27, 1980 that is believed to have been arson. Replacement costs could run as high as $500,000. The Sulphite Bridge is listed on the National Register of Historic Places.


Pratt deck truss bridge over Winnipesautee River on Former Boston & Maine Railroad (Franklin & Tilton Railroad)
Franklin, Merrimack County, New Hampshire
Closed to all traffic
Built 1896 as Covered Pratt Deck Truss, Abandoned 1976, Outer wood burned off by vandals in 1980
- Boston & Maine Railroad (B&M; BM)
- Franklin & Tilton Railroad
Covered Wooden Pratt Deck Truss
Length of largest span: 65.0 ft.
Total length: 225.0 ft.
Posted to the National Register of Historic Places on June 11, 1975
Also called
Railroad Bridge
Upside-Down Covered Bridge
BM - Upside-Down Covered Bridge
BM - Winnipesautee River Bridge
Sulphite Covered Bridge
Approximate latitude, longitude
+43.44490, -71.63524   (decimal degrees)
43°26'42" N, 71°38'07" W   (degrees°minutes'seconds")
Approximate UTM coordinates
19/286757/4813595 (zone/easting/northing)
Quadrangle map:
Inventory numbers
NRHP 75000130 (National Register of Historic Places reference number)
BH 50592 (Bridgehunter.com ID)

Update Log 

  • June 11, 2015: New photos from Royce and Bobette Haley
  • May 17, 2015: Updated by Luke: Name change via Royce's forum post.
  • January 26, 2014: New photo from Luke Harden
  • August 10, 2012: Updated by Daniel Hopkins: Added category "Railroad"
  • December 18, 2011: Updated by J.P.: Added category "Boston & Maine Railroad"
  • December 18, 2011: Photos imported by James Baughn


  • J.P. - wildcatjon2000 [at] gmail [dot] com
  • HAER NH-36 - Sulphite Railroad Bridge, Former Boston & Maine Railroad (originally Tilton & Franklin Railroad) spanning Winnipesautee River, Franklin, Merrimack County, NH
  • Luke
  • Royce and Bobette Haley - roycehaley111 [at] yahoo [dot] com


Sulphite Railroad Bridge
Posted December 18, 2011, by Tony Dillon (spansaver [at] hotmail [dot] com)

I have known about the "Upside Down Covered Bridge" since I was a kid. I knew it had been burned many years back but was pleasantly surprised to find out it is still standing. And even better to hear it is going to be put into use and preserved!

Sulphite Railroad Bridge
Posted December 18, 2011, by J.P.

I found this bridge today by accident, but anyways, this bridge is the only upside down covered bridge left in the united states. The bridge was burnt and lost its original wood covering, but still stands with the truss intact. there are plans to refurbish and open it on a trail. I'm not sure how to upload haer stuff, so I have posted the haer link on here.